OSSC Pro

[maxtherabbit]

People who use "if it fits it ships" as a guideline for selecting a power supply deserve to destroy their devices

[vol.2]

You mean like connecting a 12V PSU to a 5V device because it shares the same plug/socket?

I was thinking more like someone using a USB PSU that is inferior and can't power the OSSC Pro. Also, as I said, these are concerns mention by others, not me. In this case, Marqs mentioned in a previous post that there were signalling protocols that tell smart PSUs to supply more current, and that they are prone to errors. If you doubt that, I can't really speak to it, but I can only assume Marqs and Co. did their research about it.

From my own observations, I noticed this as a big issue with the Raspberry Pi 3 and 4. It turns out that there are a lot of USB PSUs out there with false current ratings on them, and you will end up with people just grabbing any old PSU out of a draw and hoping it works. There are copious threads on the pi forums of people using crappy supplies that they just don't understand why they don't work. Go figure.

Personally, I think that is a lot more of a potential issue than someone using a 12VDC supply to fry their OSSC. I'm not as mean about it as MTR, but yeah. In the case of USB, there's a good chance that someone is grabbing a PSU that they have every reason to believe should work, but it doesn't.

[ldeveraux]

People who use "if it fits it ships" as a guideline for selecting a power supply deserve to destroy their devices

Don't know if that was directed at me (no quote) but I mistyped. I checked the voltage and it was 500mV, I meant to say the current may have been low. Regardless, I used the OSSC with a USB barrel connector from a source that was 500mV and >=1A

[Unseen]

Of course not; if you go from USB A to a barrel connector, you're effectively guaranteed 5V power regardless of the charger, because that's what standard USB has provided for decades

Actually it's more like 4.35V to 5.25V at the device input according to spec and possibly even less in practice with a low-quality cable and a high-current device.

The problem instead is that, unlike USB, barrel plugs do not guarantee a specific voltage.

EIAJ RC-5320A does, but I don't remember any implementations of it outside of Sony devices.

If I wasn't paying attention and plugged this into my OSSC instead of the 5V PSU I got with it, I'd have to be online looking for either some replacement parts or a new OSSC.

According to the schematics, the OSSC has a fuse and a Zener diode on the input, if you plug a 12V PSU into it the fuse should blow even before you turn on the OSSC's power switch.

[Konsolkongen]

Don't know if that was directed at me (no quote) but I mistyped. I checked the voltage and it was 500mV, I meant to say the current may have been low. Regardless, I used the OSSC with a USB barrel connector from a source that was 500mV and >=1A

You're definitely mistyping here as well. Surely you didn't run your OSSC from a 0.5V PSU

[ldeveraux]

Don't know if that was directed at me (no quote) but I mistyped. I checked the voltage and it was 500mV, I meant to say the current may have been low. Regardless, I used the OSSC with a USB barrel connector from a source that was 500mV and >=1A

You're definitely mistyping here as well. Surely you didn't run your OSSC from a 0.5V PSU

Correct. OK now I don't remember what the hell I did! I'm going to the corner to think for an hour.

[nmalinoski]

If I wasn't paying attention and plugged this into my OSSC instead of the 5V PSU I got with it, I'd have to be online looking for either some replacement parts or a new OSSC.

According to the schematics, the OSSC has a fuse and a Zener diode on the input, if you plug a 12V PSU into it the fuse should blow even before you turn on the OSSC's power switch.

Thank you for the responses. Is that fuse a one-and-done or self-resetting?

[6t8k]

^ The former, so you'd have to replace that. The part number is F0603E1R50FSTR if you're interested. The SD05-7 Zener diode is specified to break down between 6.2V and 7.3V, so between 5V and about 6.75V, there's a potential that parts on the OSSC that come after the fuse might become subject to adverse voltage levels. On the second page of this thread, marqs wrote that the OSSC Pro will feature (better) overvoltage protection.

[djc5166]

^ The former, so you'd have to replace that. The part number is F0603E1R50FSTR if you're interested. The SD05-7 Zener diode is specified to break down between 6.2V and 7.3V, so between 5V and about 6.75V, there's a potential that parts on the OSSC that come after the fuse might become subject to adverse voltage levels. On the second page of this thread, marqs wrote that the OSSC Pro will feature (better) overvoltage protection.

I did this once to my ossc v1.5. The PSU is/was identical to the one supplied with the gscartsw, but is a different voltage.

Just had to replace this diode and everything was good again.

[marqs]

Prototypes finally arrived last week and are next shipped to other developers.



Some development HW in another picture:

Spoiler

From top to bottom, left to right:

* DExx-vd_isl v1.1 add-on board on DE2-115
* DExx-vd_isl v1.2 add-on board on DE10-Nano
* Unfinished SiI1136 HSMC daughtercard (for testing alternative HDMI TX on DE2-115 etc.)
* UMFT602A-B HSMC daugthercard (for testing FT602Q on DE2-115 etc.)

[NormalFish]

Looking good!

[6t8k]

It looks phenomenal. Grand milestone!

I wonder whether the case will do without a fan.
Were you able to experiment some with the FT602 daughtercard already?

[DirkSwizzler]

WANT

[ldeveraux]

Why are there no HDMI in/out on the dev boards?

[Downcry]

This looks amazing.
Someday I hope there’s a mini, HDMI-only version.

[GigaBoots]

Looks great. I wait patiently with immense anticipation.

[nmalinoski]

This looks amazing.
Someday I hope there’s a mini, HDMI-only version.

I feel like this is unlikely; I feel like the parts cost of the analogue inputs is insignificant compared to the rest of the system; it's certainly doable, but savings over the regular OSSC Pro would be minimal, if any.

[bobrocks95]

This looks amazing.
Someday I hope there’s a mini, HDMI-only version.

Do you have that many retro consoles outputting low res HDMI?

[Downcry]

This looks amazing.
Someday I hope there’s a mini, HDMI-only version.

Do you have that many retro consoles outputting low res HDMI?

Well, for instance: every wiidual/gcdual/AVS/etc is limited to something less then 1080p.
Every other console HDMI mod is limited 1080p.

I realize the pro will likely be limited to 1080p also, but my point is that there are lots of HDMI-outputting devices that can’t drive most modern displays at their native resolutions. (1440p and up)

[lechu]

I know this is a long shot, and I know it *can* happen, but what are the odds of something like a Pro-lite, with just six jack input (r g b s and audio) and HDMI in? The original OSSC can accept all types of video through scart or vga, and having an option with just a single input and HDMI could cut down production costs and costs to the consumer.

[ldeveraux]

I know this is a long shot, and I know it *can* happen, but what are the odds of something like a Pro-lite, with just six jack input (r g b s and audio) and HDMI in? The original OSSC can accept all types of video through scart or vga, and having an option with just a single input and HDMI could cut down production costs and costs to the consumer.

Zero odds.

[SavagePencil]

How would downscaling work with this? Would analog out be on a board attached to GPIO?

[ryu]

so this is gonna work with snes consoles out of the box and doesn't require another device inbetween to fix the sync?

[6t8k]

How would downscaling work with this? Would analog out be on a board attached to GPIO?

Downscaling and analog video output are two distinct concepts/features, only loosely related to each other. Downscaling can be done in the FPGA, but could also be done by an expansion board – while the FPGA e.g. does upscaling and outputs that via the on-board HDMI transmitter chip, or merely passes through what is received via the analog or digital inputs. Analog video output could be achieved either by feeding the digital video output by the Pro (or an expansion board connected to the Pro) into a separate DAC like for example the Portta boxes – or by an OSSC Pro expansion board that contains a DAC.

so this is gonna work with snes consoles out of the box and doesn't require another device inbetween to fix the sync?

NES/SNES compatibility with the OSSC Classic is varied to begin with and depends largely on the sink's ability to sync to the signal despite the jitter in it, which propagates from the console through the OSSC Classic to the sink due to the way the OSSC Classic works. The higher the line multiplication factor, the higher the severity of the jitter when it reaches the sink, and therefore the chance that the sink is unable to process the signal properly. For example, I can use my SFC in combination with (up to) Line4x just fine with my 1080p monitor and capture card, but both bail out when I switch to Line5x.

That said, the OSSC Pro has ways to absorb/sidestep the jitter that occurs with an unmodified console:

- Thanks to the on-board Si5351C clock generator, the video digitizing chip's sampling clock can be made independent from the output video clock. The OSSC Classic derives its input sampling clock and output HDMI pixel clock from the console's (jittery) sync signal at all times; the OSSC Pro doesn't have to, as it can generate clock signals on its own.
- Pins 3 and 4 of the expansion port could accept the console's master clock signal, which sampling clock could then be derived from. Rather experimental, but compared to the above option it would have the advantage of avoiding a very slight stutter/latency increase and implicating optimal H.samplerate and -phase at all times.

jotheripper tested a region/60Hz modded PAL SNES (therefore exhibiting the jitter problem) with the OSSC Classic on the one hand, and the DE-10 Nano+vd_isl combination on the other hand, using the same digital TV. In the former scenario, the TV could only display 240p input up to Line2x mode, and in the latter, it could go up to Line5x, which is also promising. I'm soon going to conduct some tests on my own with DE-10 Nano+vd_isl.

[marqs]

The new video ADC is indeed more robust than the one in classic model so it's more likely to attenuate jitter to a level where the signal is accepted by a larger number of displays. For those which still can't, there'll be the option to disable framelock by using external sampling/output clock as mentioned which should result to 100% compatibility.

Were you able to experiment some with the FT602 daughtercard already?

Not yet, but that one and Sil1136 daughercards are something I should evaluate sooner than later since results especially from the latter can still affect design of the final HW. Unfortunately my spare time is limited, and there's some new games coming out soon as well which will eat away dev time.

[vol.2]

- Pins 3 and 4 of the expansion port could accept the console's master clock signal, which sampling clock could then be derived from. Rather experimental, but compared to the above option it would have the advantage of avoiding a very slight stutter/latency increase and implicating optimal H.samplerate and -phase at all times.

In this case, you would have to expose the SNES clock signal with a connector, I assume? What would that look like, a phono connector output on the back of the console or something?

[6t8k]

In this case, you would have to expose the SNES clock signal with a connector, I assume? What would that look like, a phono connector output on the back of the console or something?

An RCA/phono connector could work, especially if a well shielded cable (concentric braid/foil) is used. Some considerations about avoiding potential difficulties:

- Cable length would sooner become a factor in terms of signal degradation as compared to say, a similar cable transmitting an analog component video signal.
- Ideally, cable length would be close to the length of the cable that's transmitting the video signal, otherwise sampling phase could be off due to a difference in transmission delay (but that could be corrected to some degree of granularity on the OSSC Pro's side).
- The impedance transitions between a) the connector on the console and the cable, and b) the connector on the OSSC Pro and the cable, should ideally be kept minimal, otherwise interference caused by reflected parts of the signal might result in trouble.
- While the signal is not being used for sampling, the connector on the console should still be impedance matched to avoid reflections impairing the function of the console, e.g. by keeping the cable plugged in on both ends or by terminating the connector with a resistor between the signal and GND.
- According to the current pinout diagram for the expansion port, pins 3 and 4 don't have a level shifter behind them, so the 5V TTL signal would have to be brought down beforehand to a voltage level compatible to an I/O standard supported by the Cyclone V – or perhaps the signal could also be accepted on one of the EXP_IO_B pins.

[kerframil]

I welcome the addition of an adaptive line multiplier and scaling capabilities. I just bought an OSSC and, as much as it serves its intended purpose correctly, I was dissastisifed because its 480p/Line2x output mode is worse than the XRGB-Mini at 720p. At least, when paired with my KDL-55W905A, which doesn't support any of the other modes. Between that, and support for games in tate mode, you could have a real winner on your hands.

[jotheripper]

@6t8k
i tested the de10-vd_isl on my original playtronic snes pal60 system. this was special for the brazilian market.

today i had some test with my pal sega saturn 313p in line4x 1080p mode..its awesome.

[vol.2]

- While the signal is not being used for sampling, the connector on the console should still be impedance matched to avoid reflections impairing the function of the console, e.g. by keeping the cable plugged in on both ends or by terminating the connector with a resistor between the signal and GND.

That could be done with a headphone jack. There are phones jacks used on equipment that has internal speakers which are designed to switch an external transistor network when a plug is present. (essentially to route audio away from the speakers and turn them off) That kind of switch could be used to close a resistor when unplugged.

- According to the current pinout diagram for the expansion port, pins 3 and 4 don't have a level shifter behind them, so the 5V TTL signal would have to be brought down beforehand to a voltage level compatible to an I/O standard supported by the Cyclone V – or perhaps the signal could also be accepted on one of the EXP_IO_B pins.

Probably be best done inside the console. Not a huge deal. I guess the question is whether or not this is a bigger pain in the ass than just doing the de-jitter mod?